A pretty simple yet very effective laser boat I've been running for a while now. You can usually get two consecutive alpha strikes out of this build without overheating (definitely if you've got the two basic heat management unlocks), and when you're near the top of your heat bar you can dish out a near-constant barrage of large laser fire just using the arms. Full armour (or as good as) means you're not likely to go down quick, though obviously you need to watch your side torsos with that XL engine. Even so, with the speed you've got you can usually get away from serious trouble if your sides start peeling. Originally I ran this build with a 245 XL engine, Endo and standard HS - this gave marginally higher heat efficiency, but with the slow speed of it I actually found myself overheating more as I was stuck in the thick of the brawl. With the 300 XL, DHS and no Endo you're at the limit of the amount of cooling you can fit, but I think it works fine. If you really wanted you could strip down some armour and throw in AMS, but at 70kph you should be able to get cover from LRM fire anyway. Weapon groupings I use: Mouse 1: Left Arm Mouse 2: Right Arm (chainfire sometimes) Mouse 3: Both Torsos Mouse 4: Alpha Strike This mech actually got me to finally change the binding for Mouse 1 to just fire Group 1 - with it firing the selected group it was a pain to toggle the chainfire on the right arm. Now I can just select Group 2 at the start of the round and tap backspace if I need more careful heat management or I want to deliver more damage to a fast light.